Various systems of data-entry terminals have been heretofore developed which enable the entry of data for data processing from a plurality of different locations. For example, prior systems have utilized a plurality of point-of-sale terminals in a retail store environment to enable sales data to be entered at a plurality of locations about a retail establishment. In such prior point-of-sale systems, the terminals have often been connected to a common data bus and the data directed to a common computer host which may be located at the retail establishment or at a remote location. Such systems are relatively bulky and expensive due to the requirement of a large and complex separate host data processing computer or controller for storing input data.
In order to eliminate the requirement of a separate on-line host data processing computer, stand-alone terminals have been previously developed utilizing magnetic storage cassettes which are used to record sales data from each terminal. The cassettes may then be subsequently removed and taken to a remote location for subsequent processing.
In point-of-sale terminal systems, it is necessary to perform arithmetic operations on sales data with the use of various function programs. In one type of point-of-sale system using a magnetic tape cassette, function programs for operating on point-of-sale data are permanently stored in read-only memories in each of the terminals. In another type of such prior systems, function programs are input into each of the terminals at the beginning of the day when the system is powered up. In both types of prior systems, there has been a requirement for storage in each of the terminals for function programs which are required to be executed during operation of the terminals. Such prior systems have thus required a plurality of separate storage facilities in each point-of-sale terminal to provide the desired operations.
A need has thus arisen for a point-of-sale data-entry terminal sytem wherein the data-entry terminals are self-contained in unitary portable housings without the requirement of an additional data recording housing or a separate controller time-shared among plural terminals. A need has also arisen for point-of-sale data terminals wherein all function or application programs are not permanently wired into read-only memory or the like, and yet wherein each terminal can perform a broad and variable range of functions independently of any connection to a programmable host computer or the like.
In brief, the computerization of the point-of-sale terminal has heretofore not taken full advantage of the flexibility inherent in the use of programmable processors, because conventional terminals are dependent upon unchangeable internally stored function programs and/or connections to external controllers or host processors.